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s390/mm: Add huge page dirty sync support

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To do dirty loging with huge pages, we protect huge pmds in the
gmap. When they are written to, we unprotect them and mark them dirty.

We introduce the function gmap_test_and_clear_dirty_pmd which handles
dirty sync for huge pages.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
Janosch Frank
2018-07-17 13:21:22 +01:00
parent 6a3762778d
commit 0959e16867
5 changed files with 148 additions and 44 deletions
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34
arch/s390/mm/pgtable.c
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@@ -704,40 +704,14 @@ void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
/*
* Test and reset if a guest page is dirty
*/
bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
bool ptep_test_and_clear_uc(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
spinlock_t *ptl;
pgd_t *pgd;
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pgste_t pgste;
pte_t *ptep;
pte_t pte;
bool dirty;
int nodat;
pgd = pgd_offset(mm, addr);
p4d = p4d_alloc(mm, pgd, addr);
if (!p4d)
return false;
pud = pud_alloc(mm, p4d, addr);
if (!pud)
return false;
pmd = pmd_alloc(mm, pud, addr);
if (!pmd)
return false;
/* We can't run guests backed by huge pages, but userspace can
* still set them up and then try to migrate them without any
* migration support.
*/
if (pmd_large(*pmd))
return true;
ptep = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (unlikely(!ptep))
return false;
pgste = pgste_get_lock(ptep);
dirty = !!(pgste_val(pgste) & PGSTE_UC_BIT);
pgste_val(pgste) &= ~PGSTE_UC_BIT;
@@ -753,11 +727,9 @@ bool test_and_clear_guest_dirty(struct mm_struct *mm, unsigned long addr)
*ptep = pte;
}
pgste_set_unlock(ptep, pgste);
spin_unlock(ptl);
return dirty;
}
EXPORT_SYMBOL_GPL(test_and_clear_guest_dirty);
EXPORT_SYMBOL_GPL(ptep_test_and_clear_uc);
int set_guest_storage_key(struct mm_struct *mm, unsigned long addr,
unsigned char key, bool nq)